In a network evolution process of an LTE (Long Term Evolution, Long Term Evolution) system or an LTE-A (LTE-advanced, Long Term Evolution Advanced) system of the 3GPP (3rd Generation Partnership Project, 3rd Generation Partnership Project), a trend of evolution from a homogeneous network to a heterogeneous network emerges.
To increase a network coverage capacity, small cell nodes are added to the heterogeneous network on a basis of macro station node coverage. With ever-growing capacity requirements, the small cell nodes are intensively deployed. However, during intensive deployment, a problem of transmitting data of a small cell node to a CN (Core Network, core network) needs to be resolved.
At present, the small cell node in the heterogeneous network may connect to an ideal backhaul node (for example, the “ideal backhaul node” accesses the core network by using a fiber or an extremely high frequency microwave, and capacities of these nodes accessing the core network may be considered as unlimited, thus an “ideal connection”) in a wireless transmission access manner, so as to access the core network. However, because an ideal backhaul node used by the small cell node to access the core network is fixed at present (for example, an LTE Rel-10 relay node fixedly selects an ideal backhaul node to access the core network), that is, a backhaul path is fixed, and a service served by each small cell node changes dynamically, load of an ideal backhaul node 1 is relatively high at a particular time point, and load of another ideal backhaul node (such as an ideal backhaul node 2) is relatively low. However, a small cell node associated with the ideal backhaul node 1 still accesses the ideal backhaul node 1, that is, still selects the fixed backhaul path. In this case, the ideal backhaul node 1 cannot well serve all small cells accessing the ideal backhaul node 1, which causes relatively small capacities in some small cell nodes and relatively low data transmission efficiency. The ideal backhaul node 2 is idle in this case. A small cell of the ideal backhaul node 1 cannot reselect a transmission path according to this situation or perform transmission by using the ideal backhaul node 2, resulting in a waste of capacity resources.
For example, as shown in FIG. 1A, at a moment, both a small cell node 1# and a small cell node 2# have high load (that is, all users served by the small cell node 1# and the small cell node 2# have relatively large service transmission requirements). An ideal backhaul node that can be accessed by the small cell node 1# and the small cell node 2# is an ideal backhaul node A. Limited by an air interface capacity, the ideal backhaul node A cannot provide the small cell node 1# and the small cell node 2# with relatively high capacities at the same time. In this case, capacity requirements of the small cell node 1# and the small cell node 2# certainly cannot be met. A small cell node 3# has low load in this case and has not too many capacity requirements, and in this case, an ideal backhaul node B that can be accessed by the small cell node 3# has remaining capacity resources for provision.
To improve a capacity of a small cell node and improve capacity resource utilization, a dynamic wireless transmission path selection method according to a service status of the small cell node is provided. In this case, the small cell node is a wireless transmission path selection node. Certainly, the wireless transmission path may be selected by a small cell node, or may be selected by another node, such as a central control node. For example, when the foregoing example is further used for description, if a capacity requirement of the small cell node 2# cannot be met, instead of selecting a wireless transmission path with the ideal backhaul node A to access the core network, the small cell node 2# may select a wireless transmission path with the ideal backhaul node B to access the core network, which is a wireless transmission path shown by a dashed line in FIG. 1A. The small cell node 2# may also be referred to as a wireless transmission path selection node 2#.
In the prior art, a wireless transmission path selection process for a wireless transmission path selection node is mainly as follows: A propagation loss of each wireless transmission path to the wireless transmission path selection node is determined. Then, assuming that a propagation path is a path corresponding to a signal source and another propagation path is a path corresponding to an interference source, receive power of the “signal source” path and receive power of the “interference source” path are obtained by means of calculation according to path losses and transmit power that are of the corresponding propagation paths. A signal to interference plus noise ratio (SINR) of a wireless transmission path is calculated when the wireless transmission path is assumed as the wireless transmission path on which the signal source is located, and the SINR is used as a channel quality indicator (CQI). A wireless transmission path on which the “signal source” is located and that has a highest CQI or has a highest criterion calculated according to the CQI (for example, a link capacity is obtained according to the CQI and available bandwidth information) is used as a target wireless transmission path, so as to access the core network by using the target wireless transmission path. However, because only a propagation loss is considered during wireless transmission path selection, in this method, there is a disadvantage of relatively low accuracy of a selected wireless transmission path due to a relatively large deviation of a calculated CQI.
Certainly, in practical application, a wireless transmission path also needs to be selected in another application scenario. For example, during peer-to-peer mesh network transmission, each node that forms the mesh network may find a path with highest transmission efficiency by means of dynamic wireless transmission path selection; or in device-to-device (D2D) application, a source terminal user node needs to select a path with highest transmission efficiency to arrive at a terminal user node. In the foregoing example, if a node has a multi-antenna capability (for example, the node is configured with 4 antennas) and only a propagation loss is considered during wireless transmission path selection, there is still a disadvantage of relatively low accuracy of a selected wireless transmission path due to a relatively large deviation of a calculated CQI.
In conclusion, a disadvantage of inaccuracy of a determined wireless transmission path and relatively low resource utilization exists in the existing wireless transmission path selection method.